Functionalized chitosan-based coatings for active corrosion protection

• Chitosan-based coatings loaded with organic corrosion inhibitor are developed.
• The surface properties of the chitosan coatings were improved by chemical grafting.
• The developed coatings confer active corrosion protection to aluminum alloys.

Chitosan-based coatings were suggested in this work as a “green” alternative for active corrosion protection of aluminum alloys. 2-Mercaptobenzothiazole (MBT) was used here as an efficient corrosion inhibitor for AA2024. The electrochemical impedance spectroscopy has demonstrated a strong inhibiting action of MBT showing no corrosion attack even after one week in full immersion tests when MBT-loaded chitosan coatings are applied.The surface properties of the chitosan coatings were improved by chemical grafting with poly(ethylene-alt-maleic anhydride) (PEMA) and poly(maleic anhydride-alt-1-octadecene) (POMA), aiming at increasing hydrophobicity that is crucial for corrosion protection in atmospheric conditions. The high contact angles, in the range of 140°, were obtained on the MBT-containing chitosan films.